My DK is great at dps, but i want to try and tank. im duel speced and currently in PVP spec as an off-spec. I plan on switching it over to tank, but i see DK tanks either in blood or frost.....and im kinda confused on which i need to follow. Any tips would be appreciated.

There are different advantages in both Blood and Frost spec tanking. It kind of depends on your playing style. For example, I do Unholy Tanking, which is highly unusual these days. But that is becouse I love to do it and its my kind of style.

However, if you are new to tanking I highly suggest Frost or Blood. Just see what fits your playing style. I will post the spec for ya if you want and also your rotation macro.